package com.leetcode.code;

import java.util.HashMap;
import java.util.Map;

public class LeetCode0001Java {

    public static void main(String[] args) {

    }

    int[] nums = { 2, 7, 11, 15 };
    int trager = 9;

    public int[] twoSum(int[] nums, int target) {
        Map<Integer, Integer> map = new HashMap();
        for (int i = 0; i < nums.length; i++) {
            map.put(nums[i], i);
        }
        for (int i = 0; i < nums.length; i++) {
            int complement = target - nums[i];
            if (map.containsKey(complement) && map.get(complement) != i) {
                return new int[] { i, map.get(complement) };
            }
        }
        throw new IllegalArgumentException("No two sum solution");
    }
}

// 一次哈希表
//    public int[] twoSum(int[] nums, int target) {
//        Map<Integer, Integer> map = new HashMap();
//        for (int i = 0; i < nums.length; i++) {
//            int complement = target - nums[i];
//            if (map.containsKey(complement)) {
//                return new int[] { map.get(complement), i };
//            }
//            map.put(nums[i], i);
//        }
//        throw new IllegalArgumentException("No two sum solution");
//    }
